In a network where Internet operates under IPv6, IPv6 address shall be assigned to each constituent network element. IPv6 addresses are logically divided into two parts: a 64-bit (sub-)network prefix and a 64-bit interface identifier. A network prefix is normally associated with a specific domain, which means that a data packet designated to an IPv6 address comprising the network prefix may be routed to a router/network entity located in that specific domain.
On top of IPv6, PMIPv6 may be deployed as a network layer protocol for managing mobility of mobile nodes (MN) as depicted in FIG. 1. In PMIPv6 domain, there are two important network entities—Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG). MAG is a function on an access router that manages the mobility related signaling for a MN attached to its access link, e.g. a radio link. LMA is the home agent for a MN in PMIPv6 domain. A mobile node identifier (MN-ID) may be assigned to a MN in PMIPv6 domain. It is a stable identifier of a MN that mobility entities in PMIPv6 domain can always acquire and use for predictably identifying a MN. This is typically an identifier such as a network access identifier (NAI) or other identifier such as a media access control (MAC) address.
When a MN initially tries to attach to a network, a Home Network Prefix (HNP) is generated in LMA and assigned to the link between the MN and a MAG, e.g., MAG1 as shown in FIG. 1. The home network prefix is anchored at LMA (which means that a data packet designated to an IPv6 address comprising the prefix as its network prefix would be routed to LMA) and indicates the home network of the MN. More than one prefix can be assigned to the link between MN and MAG according to PMIPv6. The MN may configure its interfaces with one or more addresses from the obtained home network prefix, e.g. home network prefix+an interface identifier. When the MN roams, a handover in access link layer may be performed and as the result, the MN may be connected with a new MAG, e.g., MAG2, located in a different domain than MAG1. However, due to the originally assigned HNP, all the IP traffic is delivered to and from the MN via LMA and MAG2. Moreover, the home network associated with the home network prefix may be in completely different domain (e.g. Domain 3) than MAG2 which is located in Domain 2. When traffic volumes grow significantly and the majority of the IP services are provided locally in IP topology wise, the LMA could easily become a bottleneck as it may become the traffic concentrator for multiple MAGs.